Hepatitis C caused by hepatitis C virus (HCV) infection has been extensively studied in the last two decades, but it still remains difficult to treat due to incomplete information on HCV. At present, there is only one drug, Ribavirin, approved by Food and Drug Administration (FDA) for treating hepatitis C (Thomas et al., Hepatology 20(4):440, 1994), which is a purine nucleoside derivative. Interferon-α having antiviral activity against a wide spectrum of DNA and RNA viruses has been suggested as a therapeutic for hepatitis C. However, they are considered to be inappropriate for clinical application due to serious side effects and their low curative effect. Although therapy with Ribavirin-interferon-α combination has shown an improved result, it still exhibits low specificity for hepatitis C virus and low curative effect, besides the accompanying side effects such as anemia and depression. Accordingly, a new therapeutic for hepatitis C having improved curative activity and reduced side effects is required.
Some pyrimidinedione derivatives have been developed for use as an antiviral agent for treating AIDS. For example, Korean Patent Laid-open Publication 2000-65885 discloses novel pyrimidinedione derivatives synthesized by introducing a homocyclic, or alky or alkylcarbonylmethy group to the N-1 site of pyrimidinedione. The disclosure suggests that said pyrimidinedione derivatives have strong pharmacological activity against human immunodeficiency virus (HIV) in the absence of toxicity. We have unexpectedly found that such pyrimidinedione derivatives are effective in preventing or treating hepatitis C.